1. Field of the Invention
The present invention relates to a method of manufacturing a silicon single crystal, and in particular, to a method of manufacturing a highly-doped silicon single crystal by using a Czochralski method.
2. Description of the Related Art
Conventionally, there has been used a method of adding a dopant to a silicon melt while pulling up silicon single crystal, as one of methods of manufacturing silicon single crystal having a desired property such as desired specific resistance in the Czochralski method in which seed crystal is brought into contact with silicon melt in a crucible and the seed crystal is pulled up while being rotated to grow a silicon single crystal thereon.
As a method of adding a dopant to silicon melt while single crystal is pulled up by using the Czochralski method, there is generally known a method in which a dopant is added to silicon melt in a crucible in mid-process of pulling up silicon single crystal by using an impurity introducing device including an accommodation container for accommodating a dopant (impurity) and a vertical movement device for inserting/retracting the accommodation container into/from the crucible, so that specific resistance of the silicon single crystal is varied discontinuously in a crystallographic axis direction (refer to, for example, JP 2005-336020 Laid-Open).
Yet further, there is also known a method in which, in a case where a dopant is added to silicon melt during pulling-up of silicon single crystal, the dopant is added at a relatively low concentration until a first half portion of a straight body section of the silicon single crystal is formed and then the dopant is added at a relatively high concentration in order to prevent dislocation from occurring due to addition of the dopant in the pulled-up silicon single crystal (see, for example, JP 2008-266093 Laid-Open).